The home icon and discussion topic drop-down icon now have text that is
visible only to screen readers. The visual change between the icon and the
topic name with down-arrow is now achieved with the CSS visible property
instead of the opacity property, so only one at a time will be visible to
screen readers as well as visually.

Enable display of course org, num in receipt page.

Verification: abstracting out specific color-based Sass variables to be *somewhat* friendly to theming

edx.org: revises course register button background for all cases (verified, riught column, and bottom of page)

edx.org: adds background to register button's html body element for visual blending in course detail view

* Uses override_settings to provide test variable
* Move location of cms link to upper right
* PEP8 / Pylink

Verification: syncing all submit button-type styling (including newly used element on verified view)

Switch to using decorators; refactor and cleanup tests.